1. Field of the Invention
The present invention relates to a belt guide mechanism. Specifically, the present invention relates to a belt guide mechanism for guiding an upper belt and a lower belt for sealing an axial slit of a cylinder tube of a rodless cylinder.
2. Description of the Related Art
As shown in FIG. 9, a rodless cylinder 1 is used as a means for transporting a workpiece. The rodless cylinder 1 has a seal belt 3a for avoiding entry of dust or the like from an unillustrated slit formed through the upper surface of a cylinder tube 2, and a seal belt 3b for keeping the interior of the cylinder tube 2 airtight.
The pair of seal belts 3a, 3b are disposed integrally with a slider 4. The pair of seal belts 3a, 3b are guided by belt separators 6a, 6b which are connected to both ends of a piston yoke 5, holder plates 7a, 7b, and upper surfaces of wear rings 9a, 9b. Pistons 8a, 8b are inserted respectively inside the wear rings 9a, 9b. 
In the conventional rodless cylinder 1, sliding sections of the pair of seal belts 3a, 3b are guided by guide members of six or more parts (for example, the pair of belt separators 6a, 6b, the pair of holder plates 7a, 7b, and the pair of wear rings 9a, 9b) disposed on both sides of the seal belts 3a, 3b. 
However, the assembling operability and the operation efficiency are unsatisfactory because a number of the guide members for guiding the seal belts 3a, 3b is large. Further, the dimensional accuracy of the guide member and the positional accuracy upon the assembling are unsatisfactory due to the influence of the dimensional error of the respective guide members.
Further, the sliding resistance is large between the seal belts 3a, 3b and the guide members, and the durability of the seal belts 3a, 3b and the guide members is low.
Furthermore, the cost is high because the number of components making up the guide members is large.
It is a general object of the present invention to provide a belt guide mechanism which reduces a number of components for guiding a first belt (upper belt) and a second belt (lower belt), thereby enabling the assembling operability to be improved.
A principal object of the present invention is to provide a belt guide mechanism which improves durability of a belt guide member.
Another object of the present invention is to provide a belt guide mechanism which reduces the cost.
According to the present invention, a first guide member has a belt separator for separating a first belt (upper belt) and a second belt (lower belt) from each other, and a holder section for pressing the first belt. The belt separator and the holder section are integrally disposed in the first guide member. Accordingly, it is possible to reduce the number of components. Therefore, it is possible to further improve the assembling operability and the operation efficiency.
The guide member conventionally made up of a belt separator and a holder plate is integrated into only a first guide member. Accordingly, there is no dimensional error which conventionally generates between the belt separator and the holder plate. Therefore, it is possible to improve the dimensional accuracy of the belt guide member.
That is, the dimensional and positional accuracy of the first guide member is improved for the first belt and the second belt to follow the first guide member with improved performance. Therefore, the sliding resistance is reduced for further improving the durability of the first and second belts and the first and second guide members.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example.